This invention relates generally to supplying oil to cylinders of internal combustion engines, and more particularly, to passive flow oiling systems for such engines.
Known engines for marine use typically include an oil lift pump which draws oil out from an oil tank, and then pumps the oil to a manifold for distribution to engine cylinders. Such pumps must be highly reliable in order to maintain adequate lubrication in the engine cylinders, and typically are expensive. In addition, and if the oil in the oil tank has thickened, e.g., due to cold whether, the oil lift pump may not draw sufficient quantities of oil from the tank during a cold start to adequately lubricate the cylinder walls, which can potentially lead to damaging the cylinders.
The present invention, in one aspect, is an oiling system for an outboard engine and includes an oil tank and an oil pump located within the tank. A manifold is coupled to the oil pump, and the manifold includes a solenoid controlled valve. The solenoid controlled valve controls the flow of oil through the manifold. The manifold further includes a plurality of check valves in flow communication with the solenoid controlled valve. The check valves are in flow communication between the solenoid controlled valve and the engine cylinders.
The oil system, in the one embodiment, further includes a pressure regulator in flow communication with, and downstream from, the manifold. An outlet of the pressure regulator in flow communication with the oil tank, and allows oil to flow from the manifold to the tank when pressure in the system exceeds a preselected pressure. The oil system also includes a fuel solenoid controlled valve coupled to receive oil from the manifold and to supply oil to the engine fuel system.
The engine includes an electronic control unit (ECU) for controlling the manifold solenoid and the fuel solenoid. In one embodiment, the ECU controls opening of the manifold solenoid valve and the fuel solenoid valve based on engine revolutions per minute.
The above described oiling system provides the advantage that the oil pump is located within the oil tank. Therefore, rather than relying upon drawing oil out of the oil tank, the above described system pumps oil from the tank. Even if the oil in the tank has thickened due to cold weather, for example, the heat generated by the pump heats the oil and causes the oil to thin out so that it can be more easily pumped through the oil supply line to the fuel system. In addition, the manifold solenoid controlled valve provides a positive control for the flow of oil to the engine cylinders, and such control reduces the likelihood of air bubbles forming in the oil line. Preventing air bubbles from forming in the oil line is important to ensure sufficient oil is provided to the engine cylinders.